SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79258646ea8371b8e9c4fd29f2a91554e34d8c63899eed170deec2a1ea378403' 
  AND token = 'SPZckbL/1BFSGPd/5F9JFe7VZZxDeXiQDgap9QNwPYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}